Integrated Expander-Motor Compressor for Dew-Point Control
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Solution Overview
Problem
Current motor-compressor units for gas processing face inefficiencies in dew-point control and compression, requiring additional compressor trains and suffering from gas migration issues due to insufficient power recovery from turbo-expanders and contamination risks.
Innovation Solution
An integrated expander-motor-compressor unit with a central shaft mechanically coupling a turbo-expander, electric motor, and compressor, allowing for gas expansion, power recovery, and efficient dew-point control, with the option for the electric motor to generate excess power for the grid when necessary, all housed in a sealed casing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a turbo-expander is used to recover power from gas expansion, then energy efficiency is improved, but the power generated is insufficient to achieve the required delivery pressure and gas migration occurs
Solution Approach 1:
The patent combines a turbo-expander, electric motor, and compressor into a single integrated unit with a common shaft. The turbo-expander recovers power from gas expansion, the electric motor supplements power when needed, and the compressor delivers the required pressure. This merging allows the system to achieve both power recovery and sufficient delivery pressure that neither component could achieve alone.
Solution Approach 2:
The common shaft serves multiple functions: it transmits power from the turbo-expander, connects the electric motor, and drives the compressor. The integrated unit performs multiple operations (expansion, power recovery, compression) in a single device, eliminating the need for separate compressor trains and reducing gas migration risks.
2Loss of energy
If gas is expanded in a turbo-expander, then mechanical power is recovered, but gas pressure in the expander becomes higher than in the compressor causing gas migration and contamination
Solution Approach 1:
By integrating the turbo-expander and compressor into a single unit with a common shaft, the patent eliminates the boundary between expander and compressor compartments. This merging removes the pressure differential that causes gas migration, as the high-pressure gas from the expander directly enters the compressor without crossing into separate compartments where contamination could occur.
3Power
If an additional compressor train is used to achieve required delivery pressure, then power requirement is met, but device complexity increases
Solution Approach 1:
The patent merges the turbo-expander, electric motor, and compressor into a single integrated unit, replacing what would traditionally require multiple separate compressor trains. This consolidation achieves the required delivery pressure while reducing device complexity by eliminating redundant components and simplifying the overall system architecture.
4Object-affected harmful factors
If a lamination valve is used to control dew point, then heavier hydrocarbons and water are removed, but power expenditure increases due to pressure drop
Solution Approach 1:
The patent converts the harmful effect of gas expansion (temperature drop causing condensation) into a beneficial dew point control mechanism. By expanding gas through the turbo-expander, the temperature naturally decreases, causing heavier hydrocarbons and water to condense and be removed. This eliminates the need for additional cooling equipment and reduces power expenditure compared to traditional methods.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enhances energy efficiency by utilizing recovered mechanical power for compression, reduces contamination risks through sealing, and allows for efficient dew-point control, while optionally generating excess power for the grid when conditions permit.
Implementation Method 1
The pressure and temperature drop across the lamination valve causes the heavier hydrocarbons and possibly water contained in the gas to condense
Implementation Method 2
Gas enters the compressor at a suction side and is delivered by the compressor at a delivery side, at a delivery pressure, higher than the suction pressure
Implementation Method 3
Mechanical coupling between the expander and the compressor is provided by a common shaft
Implementation Method 4
the electric motor delivers additional power to the central shaft
Implementation Method 5
the electric motor can switch to a generator mode and convert the available mechanical power in excess into electric power
Implementation Method 6
Gas enters the compressor at a suction side and is delivered by the compressor at a delivery side, at a delivery pressure, higher than the suction pressure
Data Source
AI summary
An expander and motor-compressor unit (1) is disclosed. The unit comprises a casing (3) and an electric motor (35) arranged in the casing (3). A compressor (37) is arranged in the casing and drivingly coupled to the electric motor (35) through a central shaft (5). Furthermore, a turbo-expander (27) is arranged for rotation in the casing (3) and is drivingly coupled to the electric motor (35) and to the compressor (37) through the central shaft (5).